This invention relates to such a reinforcing member for civil and architectural structures as is used for reinforcing beams and columns of a building, and structures such as piers of a bridge, chimneys, or the like.
Conventionally, it is normal practice, in reinforcing existing civil and architectural structures such as columns and beams of a building, a chimney, or the like, to wind reinforcing bars or wires around the portions to be reinforced and, thereafter, to coat their surfaces with mortar or paint for corrosion prevention of the reinforcing bars or the wires.
The applicants of this application previously proposed in Japanese Published Unexamined Patent Application No. 290150/1986, Japanese Published Unexamined Patent Application No. 7655/1987 and U.S. Pat. No. 4,684,567 the following reinforcing member for civil and architectural structures in order to improve the disadvantages of the reinforcing bars and wires to be used in the civil and architectural structures in that they are easily subject to corrosion and are heavy. Namely, the proposed reinforcing member is made up by forming into braided cords or ropes chemical or man-made fibers having a relatively large tensile strength such as carbon fibers, glass fibers, aromatic polyamide fibers or the like, and then hardening them by impregnating them with a thermoplastic resin.
However, the method of reinforcing by winding the above-described reinforcing bars or the like around the portion to be reinforced has the following disadvantages. Namely, it is not economical in that the coating work for corrosion prevention is time-consuming and expensive. In addition, since the lifetime of the coating is short, it becomes necessary to perform repairs again at a later date and, consequently, the structures are more likely to be damaged, than leaving them unrepaired, by the increase in weight in the repaired portion due to the weight of the added reinforcing bars or wires.
Further, it was once considered to be advantageous to use the reinforcing members made up of the above-described chemical fibers in minimizing the increase in weight of the repaired structures. However, since the reinforcing member is in the form of a bar which is hardened by impregnation of a resin, it has been found difficult to wind it around the structures, such as columns, to be repaired.